By utilizing a tri-cavity back, swingweight material is added into the heel and toe cavities for final swingweighting adjustments. The materials are weighted and comprised in two different sets. Some weights are fitted into the heel area of the club head, and are overall smaller and thinner than other weights fitted into the toe pocket. The placement of the center of gravity is met for the demands of an individual golfer by selecting one weight or the other from said weights. This will move a sweet spot inside, outside, or on the linear center of the club face. This method has proven far more effective in maintaining the heel-to-toe end-weighting design of this iron. Face-centered sweet spots give a wider sweet spot impact area, and with heavy heel-and-toe weight emphasis, greater face deflection control of the ball is built into the design.
By swingweighting directly into the head, rather than the usual practice of pouring lead down the shaft, toe weight is increased instead of being reduced. (Toe weight emphasis relates directly to slice control for the average golfer.) The two cavities used for swingweight are permanently sealed with a metal plate integral to the cavity design. The tri-cavity design as in FIG. 1 utilizes a horizontal rib that not only places weight (mass) directly behind the ball but, even more importantly, reinforces the face wall to eliminate face flex and vibration at impact. (Basic cavity back irons without this rib are subject to loss of ball compression energy through face-flexing at impact.)
Low center of gravity is one of the basic design objectives of the design to promote ball loft, and its short hosel and thin top edge, and expanding toe design fully achieve that objective. The weight and balance dynamics of the iron give maximum potential of high trajectory shots for the average player, yet does not overpower the efforts of a better player in working the ball under all playing conditions. The pronounced radius of the sole enables the player to get the club head down to the ball from divot or ragged lies. The said irons are compact, and versatile clubs. Their blunted and upturned leading edges glide the club head through heavy turf without biting and digging in to diminish head speed. Distinctive scoreline design focuses the golfer's eye on the center of the impact area for consistent shot-making.
Most of all club makers have sought to perfect the weight distribution in the golf iron head from heel to toe for the purpose of relocating the neutral axis, more commonly called the sweet spot in golf, to the center of the club face. This would give the average golfer more room for error in making contact with the ball, since added clubhead weight in the toe would resist face deflection for impacts made outside the sweet spot towards the toe. Though the single cavity low in the sole creates some endweighting and all the added weight is very low in the sole, insufficient weight is maintained directly behind the ball. It has been proven that if weight is too concentrated in the sole, the club creates lofted leverage with a corresponding amount of ball backspin--the most important club-to-ball characteristic in shot-making. Since all manufacturers attempt to produce sets of clubs for ladies, juniors, seniors, and aboveaverage adult men from the same set of investment casting molds, the basic head design must be practical from the standpoint that if special construction design elements are used--as a vent in the sole, a tungsten pellet at the extreme section of the toe and the use of three tubes into the head by other designers--clubs made for the extreme in the lightweight, swingweight and grossweight weight categories would require that only lightweight filler be used to fill these referred-to cavities. A design that creates basic and desirable weight in the toe and is subordinated to the heel yet possesses rigidity behind the impact area with the intersecting "I-beam" type design of the present invention leaves the door open for swingweight enhancement. Powdered lead and other similar metals do not provide the solid feel nor the actual weight per cubic centimeter to allow adjustments to balance of heel and toe weight. In all but the traditional professional tour play does the mere equalization of weight from heel to toe suffice. In tests and in use it has been proven that greater weight is required in the toe for the average player while the opposite is true for expert players that learned to make impact near the heel/hosel area of the club face. Thus the present invention allows even for that extreme by unweighting the toe pocket and increasing the heel weight pocket to move the center of gravity inside the linear center of the club face. To the other extreme, clubs specified for the average lady golfer require only the lightest weight, usually in the toe pocket. The overall weight of the clubs of the present invention are 20-30 grams lighter than the typical set of irons. This allows making all swingweight and gross-weight allocations directly into the back of the club head and thereby eliminate the practice of adding such weight down the shaft which unweights the toe. Use of resilient materials in the club head to lessen shock and vibration lack weight and force, while solid lead is known to absorb shock and is used in many industrial applications to do just that. Other adjustable weighting ideas were dismissed in view of the United States Golf Association's rules on golf club adjustability by simple means. Screws, bolts and other easily manipulative mechanical devices meet with resistance and generally are rejected by the United States Golf Association.